Protective Effect Of Salidroside On Rat Diabetic Retinopathy Via PI3K Pathway

ObjectiveDiabetic retinopathy（DR）is the leading cause of blindness in adults.Oxidative stress is an important mechanism of DR.Salidroside has significant anti-oxidative stress,showing beneficial effects on diabetes complication,but the effect of salidroside on DR is unclear.Therefore,this study intends to explore the protective effect and mechanism of salidroside on DR,and provide a theoretical reference for the clinical treatment of DR.MethodsMale SD rats were Intraperitoneally injected with streptozotocin to induce diabetic animal model.The experiment was divided into control group,diabetic group and salidroside group.Salidroside group diabetic rats were given salidroside by gavage,the other two groups were given blank solution.Twelve weeks later,the level of retinal malondialdehyde（MDA）and glutathione（GSH）were detected with kits,and the spatial distribution of glial fibrillary acidic protein（GFAP）was observed by immunofluorescence staining.Moreover,DIPI counterstaining was used to observe the thickness of retina from outer nuclear layer（NFL）to outer nuclear layer（ONL）.The expressions of p-PI3K,PI3K,GFAP and Caspase-3 were detected by Western blot.Results The content of retinal MDA was increased,of GSH was decreased,as well as decreased p-PI3K/PI3K,increased expression of GFAP and Caspase-3 in addition to thinner retina in diabetic group,showing significantly different to control group and salidroside group（P<0.01）.The GFAP positive staining both in control group and salidroside group were restricted to NFL layer,but almost throughout the retina in diabetic group.Conclusion Salidroside inhibits retinal oxidative stress and Caspase-3 expression in diabetic rats,at least in part through PI3K pathway,showing beneficial effects to DR.ResultsIn the control group,diabetes group and salidroside group,content of retinal GSH were（96.8±6.5）mg·g^-1,（78.1±7.6）mg·g^-1,（95.7±9.1）mg·g^-1,of MDA were（0.35±0.09）μmol·g^-1,（0.45±0.12）μmol·g^-1,（0.37±0.08）μmol·g^-1,together with the relative expression of GFAP were（36.1±4.2）%,（58.4±7.3）%,（38.2±4.9）%,of Caspase-3 were（15.2±3.7）%,（30.4±5.6）%,and（14.3±4.2）%,as well as the p-PI3K/PI3K ratios were（60.3±5.7）%,（43.7±6.1）%,and（58.4±5.3）%.The statistical results show that the content of retinal MDA was increased,of GSH was decreased,as well as decreased p-PI3K/PI3K,increased expression of GFAP and Caspase-3 in addition to thinner retina in diabetic group,showing significantly different to control group and salidroside group（P<0.01）.The GFAP positive staining both in control group and salidroside group were restricted to NFL layer,but almost throughout the retina in diabetic group.ConclusionsSalidroside inhibits retinal oxidative stress and Caspase-3 expression in diabetic rats,at least in part through PI3K pathway,showing beneficial effects to DR.